Abstract
New aromatic polyimides containing benzofuran ring were synthesized from pyromellitic acid dianhydride (PMDA) and 2, 8-diaminodibenzofuran (2, 8-DAD). The most remarkable feature of these resins were higher temperature resistance than conventional polyimides, prepared by condensation of PMDA and 4, 4′-diaminodi-phenyl ether (DDE), while the new polyimides were stiff and brittle. An investigation was undertaken to determine the effect of copolymerization of 2, 8-DAD and DDE on thermal and tensile properties of polyimide film. The more copolymerization ratio of 2, 8-DAD, the higher thermal resistance of copolymer. On the other hand the increasing of 2, 8-DAD component resulted in lowering of the molecular weight and highering of the elasticity.
